• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1679-1691
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• 2016

Successive interference cancellation (SIC) is an effective means of multi-packet reception to combat interference at the physical layer. We investigate the joint optimization issue of channel access and power control for capacity maximization in SIC-enabled wireless networks. We propose a new interference model to characterize the sequential detection nature of SIC. Afterward, we formulize the joint optimization problem, prove it to be a nondeterministic polynomial-time-hard problem, and propose a novel approximation approach based on the genetic algorithm (GA). Finally, we discuss the design and parameter setting of the GA approach and validate its performance through extensive simulations.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.121-124
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• 2002

This paper presents an adaptive digital image watermarking scheme that uses successive subband quantization (SSQ) and perceptual modeling. Our approach performs a multiwavelet transform to determine the local image properties optimal and the watermark embedding location. The multiwavelet used in this paper is the DGHM multiwavelet with approximation order 2 to reduce artifacts in the reconstructed image. A watermark is embedded into the perceptually significant coefficients (PSC) of the image in each subband. The PSCs in high frequency subbands are selected by setting the thresholds to one half of the largest coefficient in each subband. After the PSCs in each subband are selected, a perceptual model is combined with a stochastic approach based on the noise visibility function to produce the final watermark.

• Kyungpook Mathematical Journal
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• v.60 no.3
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• pp.647-671
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• 2020

In this paper, we consider the Cauchy-type problem for a nonlinear differential equation involving a Ψ-Hilfer fractional derivative and prove the existence and uniqueness of solutions in the weighted space of functions. The Ulam-Hyers and Ulam-Hyers-Rassias stabilities of the Cauchy-type problem is investigated via the successive approximation method. Further, we investigate the dependence of solutions on the initial conditions and their uniqueness using 𝜖-approximated solutions. Finally, we present examples to illustrate our main results.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.208-212
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• 2001

DQM(differential quadrature method) is applied to computation of two dimensional elasticity problems in helical spring. Elastic shear stresses in an axially loaded helical spring having rectangular and square cross sections are calculated. The results are compared with those obtained using the method of successive approximations. The differential quadrature method gives good accuracy even when only a limited number of grid points is used.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.1999-2001
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• 2001

The infinite time optimum to regulate the problem of weakly coupled bilinear systems with a quadratic performance criterion is obtained by a sequence of algebraic Lyapunov equations. The new approach is based on the successive approximations. In particular, the order reduction is achieved by using suitable state transformation so that the original Lyapunov equations are decomposed into the reduced-order local Lyapunov equations. The proposed algorithms not only solve optimal control problems in the weakly coupled bilinear system but also reduce the computation time. This paper also includes an example to demonstrate the procedures.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.2
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• pp.330-333
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• 2021

In a CNN for image classification, a SoftMax layer is usually placed at the end. The exponentinal and logarithmic operations in the SoftMax layer are not adequate to be implemented in an accelerator circuit. The operations are usually implemented with look-up tables, and the exponential operation can be implemented in an iterative method. This paper proposes a successive approximation method to calculate a logarithm to remove a very large look-up table. By substituing the large table with two very small tables, the circuit can be reduced much. The experimental results show that the 85% area reduction can be reached with a small error degradation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.6
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• pp.1250-1259
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• 2012

In this paper, a time-domain comparator is proposed for a successive approximation (SA) analog-to-digital converter (ADC) with a low power and high resolution. The proposed time-domain comparator consists of a voltage-controlled delay converter with a clock feed-through compensation circuit, a time amplifier, and binary phase detector. It has a small input capacitance and compensates the clock feed-through noise. To analyze the performance of the proposed time-domain comparator, two 1V 10-bit 200-kS/s SA ADCs with a different time-domain comparator are implemented by using 0.18-${\mu}m$ 1-poly 6-metal CMOS process. The measured SNDR of the implemented SA ADC is 56.27 dB for the analog input signal of 11.1 kHz, and the clock feed-through compensation circuit and time amplifier of the proposed time-domain comparator enhance the SNDR of about 6 dB. The power consumption and area of the implemented SA ADC are 10.39 ${\mu}W$ and 0.126 mm2, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2317-2325
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• 2016

This paper presents a 10 bit successive approximation register (SAR) analog-to-digital converter (ADC) with a reference driver. The proposed SAR ADC consists of a capacitive digital-to-analog converter (CDAC), a comparator, a SAR logic, and a reference driver which improves the immunity to the power supply noise. The reference driver generates the reference voltages of 0.45 V and 1.35 V for the SAR ADC with an input voltage range of ${\pm}0.9V$. The SAR ADC is implemented using a $0.18-{\mu}m$ CMOS technology with a 1.8-V supply. The proposed SAR ADC including the reference driver almost maintains an input voltage range to be ${\pm}0.9V$ although the variation of supply voltage is +/- 200 mV. It consumes 5.32 mW at a sampling rate of 10 MS/s. The measured ENOB, DNL, and INL of the ADC are 9.11 bit, +0.60/-0.74 LSB, and +0.69/-0.65 LSB, respectively.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.12
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• pp.65-72
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• 2008

This paper proposes a new dual-loop digital PLL(DPLL) using seamless frequency tracking methods. The dual-loop construction, which is composed of the coarse and fine loop for fast locking time and a switching noise suppression, is used successive approximation register technique and TDC. The proposed DPLL in order to compensate the quality of jitter which follows long-term of input frequency is newly added cord conversion frequency tracking method. Also, this DPLL has VCO circuitry consisting of digitally controlled V-I converter and current-control oscillator (CCO) for robust jitter characteristics and wide lock range. The chip is fabricated with Dongbu HiTek $0.18-{\mu}m$ CMOS technology. Its operation range has the wide operation range of 0.4-2GHz and the area of $0.18mm^2$. It shows the peak-to-peak period jitter of 2 psec under no power noise and the power dissipation of 18mW at 2GHz through HSPICE simulation.

• Journal of the Korean Society of Safety
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• v.12 no.3
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• pp.120-131
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• 1997

This paper presents an approximate reanalysis methods of structures based on substructuring for an effective optimization of large-scale structural systems. In most optimal design procedures the analysis of the structure must be repeated many times. In particular, one of the main obstacles in the optimization of structural systems are involved high computational cost and expended long time in the optimization of large-scale structures. The purpose of this paper is to evaluate efficiently the structural behavior of new designs using information from previous ones, without solving basic equations for successive modification in the optimal design. The proposed reanalysis procedure is combined Taylor series expansions which is a local approximation and reduced basis method which is a global approximation based on substructuring. This technique is to choose each of the terms of Taylor series expansions as the basis vector of reduced basis method in substructuring system which is one of the most effective analysis of large -scale structures. Several numerical examples illustrate the effectiveness of the solution process.